Problem: Simplify the following expression: $r = \dfrac{7a - 6}{2a + 10} \div \dfrac{1}{6}$
Answer: Dividing by a number is the same as multiplying by its inverse. $r = \dfrac{7a - 6}{2a + 10} \times \dfrac{6}{1}$ When multiplying fractions, we multiply the numerators and the denominators. $r = \dfrac{(7a - 6) \times 6} {(2a + 10) \times 1}$ $r = \dfrac{42a - 36}{2a + 10}$ Simplify: $r = \dfrac{21a - 18}{a + 5}$